-LRB- CNN -RRB- -- No one may ever know for sure whether Ohio 's execution of Dennis McGuire -- in a procedure during which he reportedly gasped , snorted and struggled -- was inhumane , but his family and medical and legal experts said Friday the ordeal points out fundamental flaws in the use of lethal injection .

McGuire , 53 , was convicted in 1994 for the rape and murder of 22-year-old Joy Stewart , who was seven months pregnant . He was executed Thursday morning at the Southern Ohio Correctional Facility in Lucasville with an injection of midazolam , a sedative , and hydromorphone , an analgesic .

Columbus Dispatch reporter Alan Johnson witnessed the event , his 19th . `` This one was different , '' he said in a posting on the newspaper 's website . `` After three to four minutes , Dennis McGuire began gasping for breath , his stomach and chest were compressing deeply , he was making a snorting sound , almost a choking sound at times .

`` And I did n't notice it at first , but his left hand -- which had been waving at his kids -- had clenched into a fist . ''

For about 10 minutes , McGuire appeared to be straining against his restraints , Johnson recalled . `` Obviously , he could n't get up , but he appeared to be trying to get up or at least raise up in some fashion . ''

Such a response should never have happened , according to Jon Paul Rion , a lawyer representing the killer 's family . McGuire 's children , Dennis Ray McGuire and Amber McGuire , were among the witnesses .

Controversial execution in Ohio uses new drug combination

`` Before the execution , there was a series of experts who testified in federal court that this is a possible to likely outcome to that procedure , '' Rion told reporters .

He said the family plans to file a lawsuit next week in federal court seeking an injunction against the state 's use of the drug combination , alleging that it represents cruel and unusual punishment and , as such , violates the Eighth Amendment to the Constitution . `` The family will be satisfied if this process stops , '' Rion said . `` That is their goal . ''

Douglas Berman , a professor at The Ohio State University and the Moritz College of Law , said in a telephone interview that such a suit would be `` groundbreaking . '' But , he added , the family did not appear to have the standing needed to file it . The family 's concern that other people should not have to endure such treatment makes `` a nice political statement , '' Berman said , but may not be enough to file a claim related to the fait accompli .

`` It 's done , '' he noted . `` There 's nothing to enjoin . ''

Deborah Denno , an expert on the death penalty at Fordham University Law School , was sympathetic to the family . `` What happened to Dennis McGuire is consistent with what a number of prominent medical experts said would happen , '' she said .

But lawyers for McGuire 's relatives need not prove he suffered to show cruel and unusual punishment , she said . Knowledge that there was a risk the procedure could have been faulty might suffice , she said .

Also , autopsy results might show evidence he did not receive enough sedative to render him unconscious , she said .

`` Ohio will have to review this new procedure they 've put in place , '' said Richard Dieter , executive director of the Death Penalty Information Center , about the drug combination that was used for the first time on McGuire . `` I think , now , the judges are going to ask more of the state and not just assume that they have it right . ''

Dieter , who opposes the death penalty , called the event `` an embarrassment '' for Ohio , but acknowledged it was not clear whether the movements witnessed by Johnson and McGuire 's relatives as well as relatives of the murdered woman were involuntary physical responses or a response to suffering .

Previously , Ohio used a single drug , pentobarbital , for many of its executions , but the manufacturer has said it did not want its product to be used in executions and the state 's stockpiles of the drug had expired , Dieter said .

The backup two-drug alternative was originally intended for use only in cases where a vein could not be found , he said .

A similar response came from the maker of propofol when Missouri considered using the drug linked to the death of Michael Jackson in an execution . Missouri gave back its supply .

As different states begin to use different drug combinations , `` some of this is a bit of an experiment , '' Dieter said .

But what happened Thursday was no experiment , a word that has a specific meaning among scientists , said Dr. Joel Zivot , assistant professor of anesthesiology and surgery at Emory University School of Medicine , who pointed out that he was not speaking for his employer . `` There is no monitoring Institutional Review Board , no ethical oversight , no gathering of data , '' he said in a telephone interview . `` This is just the state -- with the decision that it 's going to execute someone -- taking compounds and giving them to people and then seeing what happens . And then that 's all . ''

He said he was puzzled over how the court -- `` with a shrug of its shoulder '' -- could allow the possibility of cruelty taking place .

Though he , too , acknowledged that no one can be certain whether the execution caused pain and suffering , `` we can only surmise . ''

The description of McGuire 's final moments `` sounds like suffering to me , '' he said . `` All you have is how it looks and this one did n't look very good , by all accounts . ''

Zivot accused the state of `` playing doctor , and playing it poorly . ''

The problem had nothing to do with what drugs may have been used and everything to do with how they were used . `` None of these compounds are intended for the purpose of executing people , '' he said . `` They are medicine . ''

The compounds used by Ohio are in short supply , and their diversion from use in treating people to use in execution is questionable , he said . `` It 's hard to imagine that that 's ethically justifiable , '' he said .

Dr. Jonathan Groner , who has studied lethal injections , agreed that executions have been medicalized . `` We 've turned executions into outpatient surgery , '' said the pediatric surgeon in Columbus , Ohio .

But the medicalization of the procedure has been perfunctory , he said in a telephone interview , noting that neither of the two drugs used on McGuire appears to have been tested in animals for lethality . `` Thomas Edison tested the electric chair on all sorts of animals '' before it was used on people , he said .

The answer may be to return to the firing squad , which remains a legal way of execution and works surely and quickly . `` I think they take about 10 seconds , '' he said . `` And prison guards are actually trained to shoot guns ; they 're not trained to shoot drugs -- and the equipment is cheaper , too . ''

But lethal injection is called for by all 32 states that have the death penalty .

Opinion : End secrecy in lethal injections

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`` This one was different , '' says witness to execution

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McGuire was convicted in 1994 for the rape and murder of 22-year-old Joy Stewart

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Killer 's family say they will file suit next week to stop any such executions in the future

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Lawyer questions whether they have the standing to do so